Prevalence of Trichinella spp. in North Spain wild fauna and new variety of Trichinella britovi identification.

Trichinella spiralis and Trichinella britovi live in apparent sympatry among wild fauna of the Iberian Peninsula. In the present study 105 Trichinella isolates from wild mammals were typed by inter-sequence simple repeat PCR (ISSR-PCR). All isolates identified as T. spiralis were indistinguishable from the ISS48 reference strain. Among those belonging to T. britovi, four variations were clearly distinguishable; two of them, ISS11 C-76 and ISS86 MON, had been previously detected while the ISS2 reference strain and Trichinella Rioja 3, (MVUL/SP/02/R3) had not been reported before. The newly distinguished genotype of T. britovi was analyzed by ISSR-PCR, multiplex-PCR, UARR sequencing, and single larva cross-breeding with the other T. britovi genotypes including Trichinella T8 (ISS49). Among all of them, the ISS11 and ISS2 isolates were found to be the most frequent. The uniformity found within T. spiralis isolates is consistent with its recent introduction in Iberian Peninsula, whereas the presence of four variations within T. britovi suggests that this species is an endemic species. Orographical diversity of the West-End of Eurasian Region could act to preserve population diversity observed within T. britovi.

Molecular characterization of Trichinella genotypes by inter-simple sequence repeat polymerase chain reaction (ISSR-PCR).

A bulk analysis of inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR) provides a quick, reliable, and highly informative system for DNA banding patterns that permit species identification. The present study evaluates the applicability of this system to Trichinella species identification. After a single amplification carried out on a single larva with the primer 816([CA]nRY) under high stringency conditions, which provide high reproducibility, we were able to identify by consistent banding patterns 5 sibling species: Trichinella spiralis (ISS48), 2 Trichinella britovi isolates (ISS11 and ISS86), Trichinella murrelli (ISS35), Trichinella nativa (ISS71), Trichinella nelsoni (ISS29); 3 additional Trichinella genotypes: T8 (ISS149), T9 (ISS408 and ISS409), and T6 (ISS34); and the nonencapsulated species Trichinella pseudospiralis (ISS13). Moreover, 33 new Trichinella isolates from 2 zoogeographical regions were unequivocally identified. All Trichinella isolates have shown an identical pattern with those produced by the reference strain. According to these data, we have demonstrated that ISSR-PCR is a robust technique that emerges as a useful new application for the molecular identification of Trichinella isolates in epidemiological studies.

Nematocidal activity of nitazoxanide in laboratory models.

The nematocidal activity of a broad-spectrum antiparasitic agent, nitazoxanide [( N-(5-nitrothiazol-2-gammal)salicylamide; NTZ], was evaluated in both in vitro and in vivo models using Caenorhabditis elegans, Heligmosomoides polygyrus and Trichinella spiralis. In vitro, NTZ (100 muM) exhibited a low activity against C. elegans and had no effect on embryonation and hatching of H. polygyrus eggs. At concentrations of 100 and 50 muM, the inhibition of excretion/secretion of acetylcholinesterase and acid phosphatase of adult H. polygyrus by NTZ was variable. The in vitro effects of mebendazole (5 muM), albendazole (1 muM) and levamisole (10 muM) were superior to those of NTZ. In mice, NTZ at 1 g/kg proved to be inactive against preadults of T. spiralis whereas mebendazole at 10 mg/kg reduced the worm burden by up to 83%. NTZ at 1 g/kg per day for 3 consecutive days showed a low activity against adults of H. polygyrus (21% reduction). Levamisole, at a single dose of 10 mg/kg, reduced the worm burden by up to 89.9%. The results of this study suggest that NTZ would not have met criteria of a candidate compound.